One of my father's friends was asked, 20-odd years ago, whether he'd be attending the birth of his child. "Naah," he said. "Don't reckon so. More of a conception man, meself, heh heh." Have we come any further? You'd hope so. So, at first glance, Being Dad is a bit depressing. Here's a DVD intended to give men a sense of what they need to know and can expect to feel when they become fathers – and what's the notable thing about it? It's marketed at women.

"The amusing and educational DVD," it says on the front, "that will make him the perfect pregnancy and birth partner!" The insensitive old silly needs reprogramming, and he's hardly going to do it himself, is he?

Make him watch this film, and maybe something about what's actually going to happen will sift into his football-filled, beer-drinking noggin. Then, cross fingers, he won't be as much of a spare dick at the birth as he was when he got drunk (again!) at your birthday party.

The opening sequences are designed to reassure men that fatherhood won't turn you into a big blubbering girly-boy. We see men. Talking to other men. In pubs. There are pints of beer, and plates of rolls, and cutaways to cricket. The box warns, or promises: "This DVD contains male behaviour and occasional coarse language." Meet Troy, our hero. Troy is so much of a man's man that he is actually Australian. More than that, until recently he was living "the haphazard lifestyle of extreme sports holidays and kerr-azy nights out with the boys" – yet now he's a dad.

Troy's journey is your own. So it's OK to know about placentas and stuff. And look at these other guys sitting in the pub swapping war stories. They are normal men. They like footy and beer just like you.

If someone launched a video called Shopping Sensibly, with a strapline saying "The Amusing and Educational DVD that Will Make Her A Worthy Partner in the Household Finances" about a collection of girls in their pyjamas sticking pink glittery stickers on spreadsheets, I think you ladies would feel a bit patronised too.

But then again, my girlfriend, Alice, did read the baby manuals more carefully than I did. And one of the undercurrents of what turns into a sensible and even moving film is just that sense of male isolation and uselessness.

"I've never felt so emasculated," says one, of watching his partner in pain. "It is terribly distressing," says another. "Many men feel completely overtaken," says one of the experts interviewed. No shit. After 48 hours of my girlfriend struggling to give birth to our child, and crying with pain, I was in bits. I broke down on the phone to my mum.

Being Dad records 40 men in conversation around pub tables in London, Bath, Manchester, Edinburgh and Dublin. This is men talking to other men about fatherhood – when you'd think talking to women is a key part of the whole process. But what men have to say to each other matters too.

You nod in recognition. All those birth plans going tits-up. "How much," as one father eloquently puts it, "you spend on brightly coloured plastic shit." The way you end up buying about five of those pregnancy pee-sticks just in case the first couple were wrong (one man even peed on one of the sticks himself as a control). They joke nervously about sex during pregnancy, and morning sickness, and mood swings, and money shortages, and cravings. We follow a haunted-looking prospective father scouring the streets in his car for takeaway ­ Peking duck. They touch on the fear of becoming "boring", ie no longer being able to get drunk with other men so often.

They touch – fleetingly – on darker anxieties too. One man describes his first child being stillborn. The laddish premise with which Being Dad is sold isn't borne out, really, by the interviews.

Striking in this is not just the depth of the emotion, but where it takes hold. For men, pregnancy isn't somatic, obviously: so there's a moment when the knowledge comes home and the pregnancy feels real.

For each of these men it seemed to be different. For one it was the first time he felt his child kick. For another it was the positive pregnancy test. For another it was the ultrasound.

The bit that got me was the first time I heard the sound of my daughter's heartbeat: urgent, swishing, startlingly loud and fast. I was listening for the first time to a sound that is still going on in the room below me as I write this, and will not end until long after I am dead.

Obviously, like a berk, I recorded it on my phone. I listen to it now and I still feel awe and fear – like I imagine you would feel if you were an amateur astronomer who picked up the first radio signal from outer space: "Calling occupants ... We are your friends."

The outer-space analogy fits. The archetype of masculinity the film relies on is one of the man as overgrown boy: the centre of his own universe.

That's the shift. You were in a Ptolemaic universe: everything orbited round you. But when – like Troy in the end of the film – you are presented for the first time with an angry, purple, bloody, vernix-covered, shit-smeared, breathing human being, everything changes.

You are now in the Copernican universe: you are the one in orbit, and everything is suddenly in motion. It leaves you, well – unmanned.

Being Dad DVD - Pregnancy & Birth is available at Waterstones from 16th November, at £19.99.